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Contamination of food by mycotoxins occurs in minute quantities, and therefore, there is a need for a highly sensitive and selective device that can detect and quantify these organic toxins. We report the development of a rapid and highly sensitive array biosensor for the detection and quantitation of ochratoxin A (OTA). The array biosensor utilizes a competitive immunoassay format. Immobilized OTA derivatives compete with toxin in solution for binding to fluorescent anti-OTA antibody spiked into the sample. This competition is quantified by measuring the formation of the fluorescent immunocomplex on the waveguide surface. The fluorescent signal is inversely proportional to the concentration of OTA in the sample. Analyses for OTA in buffer and a variety of food and beverage samples were performed. Samples were extracted with methanol, without any sample cleanup or preconcentration step prior to analysis. The limit of detection for OTA in several cereals ranged from 3.8 to 100 ng/g, while in coffee and wine, detection limits were 7 and 38 ng/g, respectively.

Abstract Background In the past decade spherical and rod-like viruses have been used for the design and synthesis of new kind of nanomaterials with unique chemical positioning, shape, and dimensions in the nanosize regime. Wild type and genetic engineered viruses have served as excellent templates and scaffolds for the synthesis of hybrid materials with unique properties imparted by the incorporation of biological and organic moieties and inorganic nanoparticles. Although great advances have been accomplished, still there is a broad interest in developing reaction conditions suitable for biological templates while not limiting the material property of the product. Results We demonstrate the controlled synthesis of copper nanorods and nanowires by electroless deposition of Cu on three types of Pd-activated rod-like viruses. Our aqueous solution-based method is scalable and versatile for biotemplating, resulting in Cu-nanorods 24–46 nm in diameter as measured by transmission electron microscopy. Cu2+ was chemically reduced onto Pd activated tobacco mosaic virus, fd and M13 bacteriophages to produce a complete and uniform Cu coverage. The Cu coating was a combination of Cu0 and Cu2O as determined by X- ray photoelectron spectroscopy analysis. A capping agent, synthesized in house, was used to disperse Cu-nanorods in aqueous and organic solvents. Likewise, reactions were developed to produce Cu-nanowires by metallization of polyaniline-coated tobacco mosaic virus. Conclusions Synthesis conditions described in the current work are scalable and amenable for biological templates. The synthesized structures preserve the dimensions and shape of the rod-like viruses utilized during the study. The current work opens the possibility of generating a variety of nanorods and nanowires of different lengths ranging from 300 nm to micron sizes. Such biological-based materials may find ample use in nanoelectronics, sensing, and cancer therapy.

Covalently attached liquids provide a liquid–liquid surface interaction for contacting contaminants, typically achieved through use of a polydimethylsiloxane linear polymer bound to the surface at one end. The attached dimethylsiloxane polymer chain retains liquid‐like mobility through bending and rotational motions, distinguishing the coatings from those formed by crosslinked polydimethylsiloxane or branched polymer chains. Here, covalently attached liquids are reviewed and their potential for application as topcoat treatments is discussed. This review focuses on a new use scenario: prevention of chemical contamination. When allowed to age in place, chemical contaminants tend to penetrate into painted surfaces. Standard decontamination processes can fail to remove the chemicals within the paint layer, resulting in secondary exposure hazards when environmental conditions change. Covalent liquid coatings provide repellency and shedding behaviors. This review highlights the failure of typical wetting evaluations in predicting performance for the new application as well as the potential of the coatings in enhancing chemical resistance for painted surfaces. Potential methods for further improvements are also discussed. Published 2020. This article is a U.S. Government work and is in the public domain in the USA [ABSTRACT FROM AUTHOR]

Bond length alternation plays an important role in determining the conductance of molecular wires. Higher planarity of OPV makes it a better molecular wires than OPE, the measurement and theoretical calculations presented highlights an important contribution to molecular wire conductance the extent of bond length alteration along the pi-conjugated molecular backbone.

The characterization of isomeric forms of divalent hydrides of heavier group 14 elements is presented. The large co-ligands such as the beta-diketiminate ligand could stabilize divalent hydrides.

Chorismate mutase catalyzes the Claisen rearrangement of (-)-chorismate to prephenate. The importance of Arg90 is demonstrated, at the active site of Bacillus subtilis as a positively charged hydrogen bond donor involved in selective stabilization of chorismate in the transition state.

The molecular conductance of the platinum(II) complexes is significantly higher than the pi-conjugated molecular wire oligo(phenylene ethynylene)platinum(II) acetylides, which is synthesized to investigate the electrical characteristics of organometallic complexes as molecular conductors.

Biodiesel is produced by transesterification of animal fat, vegetable oil, or waste cooking oil with alcohol. After production costs, the economic viability of biodiesel is dependent on what steps are necessary to remove impurities following synthesis and the effectiveness of quality control analysis. Solid-phase extraction offers a potentially advantageous approach in biodiesel processing applications. Nanoporous scaffolds were investigated for adsorption of glycerol, a side product of biodiesel synthesis that is detrimental to engine combustion when present. Materials were synthesized with varying pore wall composition, including ethane and diethylbenzene bridging groups, and sulfonated to promote hydrogen bonding interactions with glycerol. Materials bearing sulfonate groups throughout the scaffold walls as well as those post-synthetically grafted onto the surfaces show notably superior performance for uptake of glycerol. The sorbents are effective when used in biodiesel mixtures, removing greater than 90% of glycerol from a biodiesel preparation. [ABSTRACT FROM AUTHOR]

Sorbent materials were developed utilizing two morphological structures, comprising either hexagonally packed pores (HX) or a disordered pore arrangement (CF). The sorbents were functionalized with combinations of two types of alkylammonium groups. When capture of perchlorate by the sorbents was compared, widely varying performance was noted as a result of differing morphology and/or functional group loading. A material providing improved selectivity for perchlorate over perrhenate was synthesized with a CF material using N-trimethoxysilylpropyl-N,N,N-trimethylammonium chloride. Materials were applied in batch and column formats. Binding isotherms followed the behavior expected for a system in which univalent ligands of varying affinity compete for immobilized sites. Performance of the sorbents was also compared to that of commercial Purolite materials. [ABSTRACT FROM AUTHOR]